The field of electronic data processing has reached a high level of development in the last years. As a part of the development, more and more data is exchanged between different parties. Also data that is considered as private by one party may be exchanged. A party may be willing to provide private data when the party is sure that the private data is protected against an access of an unauthorized party. An anonymization of data may be used to transform private data and thus protect the private data to a certain level when the private data is provided to a further party.
In some cases it may be useful for a party to provide private data. A party may even be willing to reveal private data to a certain degree when there is a sufficiently good reason. As an example, an enterprise may participate in a business-to-business (B2B) scenario. The enterprise may use a platform that allows a group of suppliers to see purchase announcements of a group of manufacturers. The enterprise may be a supplier and communications of the enterprise may be logged on a server with a time stamp. The time log may be considered as private because from the time log a behavior of the enterprise with regards to purchase announcements may be observed. From the behavior a manufacturer or a competitor of the enterprise may draw conclusions to the competitive situation of the enterprise and thus obtain an advantage.
However, the enterprise may be willing to provide the time log for a joint intrusion detection. In a joint intrusion detection, data from different computer systems are used to identify an intrusion, that may have been successful or not. An important possibility to identify an intrusion is a comparison of time logs of different computer systems. The time logs may be used to find suspicious communication events that have a time coincidence. A time coincidence occurs when an intruder attempts to attack more than one computer system to find a weak point in any of the computer systems.